Day31: [LeetCode簡單] 101. 對稱二叉樹

Day31: [LeetCode簡單] 101. 對稱二叉樹

題源：

來自leetcode題庫：

https://leetcode-cn.com/problems/symmetric-tree/

代碼：

dirty code湊合看吧

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    bool f(vector<int> res){
        if(res.size()==1) return true;
        for(int i=0,j=res.size()-1;i<=j;){
            if(res[i++]!=res[j--]) return false;
        }
        return true;
    }
    bool isSymmetric(TreeNode* root) {
        if(!root) return true;
        queue<TreeNode*> que;
        
        que.push(root);
        TreeNode* flag=new TreeNode(-9999);
        
        while(!que.empty()){
            que.push(flag);
            vector<int> res;
            while(1){
                auto p=que.front();
                que.pop();
                if(p==flag) break;
                if(p){
                    res.push_back(p->val);
                    que.push(p->left);
                    que.push(p->right);
                }else{
                    res.push_back(-9999);
                }
            }
            if(!f(res)) return false;
        }
        return true;
    }
};